What are the motifs in Major Pettigrew's Last Stand: A Novel by Helen Simonson?

Relationships are a recurring idea. There many interesting family and romantic relationships in the book. The main crux of the story revolves around the romantic relationship of Major Ernest Pettigrew and Mrs. Jasmina Ali. Both are widowed. Neither seems to think of the other outside their relationship at the village shop until Mrs. Ali visits Major Pettigrew to collect the money for the newspaper service. The sight of Major Pettigrew in great distress opens the door to a more personal relationship that eventually ends in marriage.